* configure: Switch from _POSIX_C_SOURCE=2 to _XOPEN_SOURCE.

We will be relying on the gettimeofday function which only came
into POSIX in 2001, but was in Unix long before then.

* HACKING: Replace notes about -D_POSIX_C_SOURCE which are not true
any more.

3 files changed, 14 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index 75bc2656..69a0ca4f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2012-04-10  Kaz Kylheku  <kaz@kylheku.com>
 
+	* configure: Switch from _POSIX_C_SOURCE=2 to _XOPEN_SOURCE.
+	We will be relying on the gettimeofday function which only came
+	into POSIX in 2001, but was in Unix long before then.
+
+	* HACKING: Replace notes about -D_POSIX_C_SOURCE which are not true
+	any more.
+
+2012-04-10  Kaz Kylheku  <kaz@kylheku.com>
+
 	* Makefile (conftest.ccver): New phony target.
 
 	* configure: The test for non-working 128 bit integers in the gcc
diff --git a/HACKING b/HACKING
index 20e4dc4f..13d9e656 100644
--- a/HACKING
+++ b/HACKING
@@ -43,10 +43,10 @@ provide rationale and make coding recommendations.
 
 Txr is written in a language that consists of the common dialect between C90
 and C++98.  The code can be built with either the GNU C compiler or the GNU C++
-compiler.  Use is made of some POSIX.2 functions, which are requested by means
-of -D_POSIX_2_SOURCE.  Also, the <wchar.h> header is used, which was introduced
-by a 1995 addendum to the C language, so it may be said that the actual C
-dialect is C95.
+compiler.  Use is made of some Unix functions from before Unix95, which are
+requested by means of -D_XOPEN_SOURCE (POSIX.1, POSIX.2, X/Open Portabiity
+Guide 4).  Also, the <wchar.h> header is used, which was introduced by a 1995
+addendum to the C language, so it may be said that the actual C dialect is C95.
 
 In coding new features or fixing bugs, care must be taken to preserve this.
 Code must continue to compile as C and C++, and not increase the portability
diff --git a/configure b/configure
index af340423..6ef68942 100755
--- a/configure
+++ b/configure
@@ -128,7 +128,7 @@ yacc_given=${yacc+y}
 yacc=${yacc-'$(cross)$(tool_prefix)$(yaccname)'}
 nm=${nm-'$(cross)$(tool_prefix)nm'}
 opt_flags=${opt_flags--O2}
-lang_flags=${lang_flags--ansi -D_POSIX_C_SOURCE=2}
+lang_flags=${lang_flags--ansi -D_XOPEN_SOURCE}
 diag_flags=${diag_flags--Wall -Wmissing-prototypes -Wstrict-prototypes}
 debug_flags=${debug_flags--g}
 inline=${inline-}